Only the hardest of hearts could deny sympathy to parents whose children suddenly develop autism or some other debilitating ailment for which there is no proven cause.
As a society, we know enough about how the world works politically and so little about how chemicals in our environment affect us medically that skepticism of official assurances can be, well, healthy.
Yet politicians, in particular, must be careful not to let a natural concern about the safety of vaccines mushroom into a public health emergency, in which fear and ignorance cause far more sickness and death than the vaccines might have.
So it's very troubling that the Maryland General Assembly is wading into the controversy over whether a mercury-based preservative, used primarily in multidose vials of flu vaccine, is linked to autism.
A statement of policy that mercury should be removed from vaccines as soon as practical might be helpful. No link to autism has been scientifically confirmed so far, but mercury is a toxin harmful to the body in large doses, and the federal government is urging drugmakers to reduce its use. Mercury is already gone from childhood immunizations.
But legislation approved by the state Senate last week attempts to ban such vaccines by Jan. 1, 2008, in a manner likely to further reduce inadequate flu vaccine supplies and raise fears about flu shots. The legislation provides an exception if vaccines mostly free of mercury are not "readily available or appropriate," but that could create such legal havoc that doctors may stop giving flu shots altogether.
Ridding the flu vaccine of mercury is tougher than dealing with other vaccinations because the shots are produced by the millions months in advance and stored in multidose vials from which the injections are drawn. Dividing them into individual doses to reduce the amount of mercury would waste about 30 percent of the supply at a time when the handful of remaining vaccine manufacturers are only producing about half of what's needed. In the event of a pandemic, the ban couldn't be lifted in time.
The private market doesn't always well serve public health needs. In this case, though, it is moving in the right direction. A political push that comes too hard and too fast would do more harm than good.